United StatesFor Fibra lines, a terminating resistor is used to prevent signal reflections from the end of the line, ensuring stable data transmission.
In wired data transmission, when the signal travels along the cable and reaches its end, if the end is not properly terminated, part of the signal can bounce back along the cable. These bounced signals, called reflections, can distort the original signal and cause communication problems.
A terminating resistor is a 120 Ω resistor that is installed on the last device on the line in a Beam or Star topology or on the last device on a branch in a Tree topology. The resistor is connected to the signal terminals (A and B) of the last device. Terminating resistors are included in the complete set of hybrid control panels.
Terminating resistors are not required when a Ring topology is used.
Some Fibra modules in the board form factor feature a terminating resistor jumper. It functions the same way as a standard terminating resistor, so there is no need to physically install a resistor between the A and B signal terminals. If such a module is the last on the line, install the jumper so that it connects two pins on the board.
If the Fibra module is the last device on the Fibra line, a terminating resistor or terminating resistor jumper (if available) must be installed on the module's input terminals. Also, terminating resistors must be installed on the last device of each line that comes out of the module's outputs. The last devices on the lines are highlighted in the scheme below.
